In The Adventures of Huckleberry Finn,  Mark Twain satirizes organized religion's aspects of manipulation and hypocrisy.

MANIPULATION

The Widow Douglas and Miss Watson perceive nothing wrong with owning slaves since they have been taught, even from the pulpit, that blacks are inferior creatures and using them as slaves is perfectly all right.

After Miss Watson tells Huck that if he prays, he can receive from Providence anything he wants.  But, when he reasons that people then should be able to regain money they have lost by praying, she explains that it is only spiritual things that one can reclaim.  This lack of logic in Miss Watson's teachings disturbs Huck.

Sometimes the widow would take me one side and talk about Providence in a way to make a boy's mouth water; but maybe next day Miss Watson would take hold and knock it all down again.

HYPOCRISY

Huck's confusion regarding what is truly moral is also apparent in Chapter XXXIII as he feels "to blame" about what has happened to the king and the duke who are tarred and feathered:

But that's always the way; it don't make no difference whether you do right or wrong, a person's conscience ain't got no sense, and just goes for him anyway.

Huck also has conflicting feelings regarding the strict teachings of Miss Watson and the choices one must make in order to survive.  For instance, he feels guilty stealing food, but he and Jim will starve if he does not.

He certainly struggles with the hypocrisy of the Fugitive Law which is promulgated as moral law in the South. Reflecting upon the mores of his society, Huck reflects in Chapter XXXI,

That's just the way: a person does a low-down thing, and then he don't want to take no consequences of it. Thinks as long as he can hide, it ain't no disgrace.

Concluding that Jim "is white inside," Huck decides against turning him in as a runaway, deicding instead "All right, then, I'll go to hell" and he tears up his letter to Miss Watson that tells her that Jim is on the Phelps's farm.